Naming instance directory by uuid in VMware Hyper.

Like Libvirt Hyper, Using EC2 template for naming instance
directory may cause conflict. we follow what Libvirt does to use
instance uuid instead of EC2 template naming. To keep backwards
compability, when fails to find a instance by uuid, fall back to use
EC2 name.

Fix bug #1186944

Change-Id: Iaba099225a9b3b0390cae4c5fbd82d7e6c11f0e0
Merge "Naming instance directory by uuid in VMware Hyper."